IPV4 / IPV6 Which Routing Protocol
(Session 13298)
Junnie Sadler, CCIE 7708
Kevin Manweiler, CCIE 5269
Date of Presentation Wednesday, August 14, 2013: 4:30 PM-5:30 PM
Session Number (13298)
Is one protocol better than the others?
Which routing protocol should I use in my network?
Should I switch from the one I’m using?
Do the same selection rules apply to IPv4 and IPv6?
How will my IPv4 and IPv6 routing protocols coexist?
2
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Is
Do You Feel Lucky?
The Questions
• Is one routing protocol better than any other protocol?
• Define “Better!” • Converges faster?
• Uses less resources?
• Easier to troubleshoot?
• Easier to configure?
• Scales to a larger number of
routers, routes, or neighbors?
• More flexible?
• Degrades more gracefully?
• …
The Questions
• The network is complex
enough to “bring out” a
protocol’s specific
advantages
• You can define a specific
feature (or set of
features) that will benefit
your network
tremendously…
The Answer Is Yes If:
The Questions
• But, then again, the
answer is no!
• Every protocol has
some features and not
others, different scaling
properties, etc.
• Let’s consider some
specific topics for each
protocol…
Before That…The Twist!
• Most likely the IPv6 IGP will not be deployed in a brand
new network and just by itself
• Most likely the existing IPv4 services are more important
at first since they are generating most of the revenue
• Redefine “Better!” • What is the impact on the
convergence of IPv4?
• How are the resources shared
between the two protocols?
• Are the topologies going to be
congruent?
• …
Which Routing Protocol
• IPv4 and IPv6 IGPs
• Convergence
• Design and Topology
Considerations
• Protocol Features
• Summary
IPv4 and IPv6 IGPs
Anonymous
9
“IPv6 Is an Evolutionary Step
“Not” a Revolutionary Step
and this is very clear in the case of routing
which saw minor changes even though most of the
Routing Protocols were completely rebuilt.”
The Mainframe Supported Routing Protocols
RIP RIPv2 for IPv4
RIPng for IPv6
Distinct but similar protocols with RIPng taking advantage of IPv6 specificities
OSPF
OSPFv2 for IPv4
OSPFv3 for IPv6 > OMPROUTE Support for OSPFv3 - z/OS V1R6
Distinct but similar protocols with OSPFv3 being a cleaner implementation
that takes advantage of IPv6 specificities
Static Default Gateway / Next Hop Routing
For all intents and purposes, same IPv4 IGP network design concepts apply to the IPv6 IGP network design
IPv6 IGPs have additional features that could lead to new designs
The Network Supported Routing Protocols
RIP RIPv2 for IPv4
RIPng for IPv6
Distinct but similar protocols with RIPng taking advantage of IPv6 specificities
OSPF
OSPFv2 for IPv4
OSPFv3 for IPv6
Distinct but similar protocols with OSPFv3 being a cleaner implementation
that takes advantage of IPv6 specificities
IS-IS Extended to support IPv6
Natural fit to some of the IPv6 foundational concepts
Support Single and Multi Topology operation
EIGRP Extended to support IPv6
Some changes reflecting IPv6 characteristics
For all intents and purposes, same IPv4 IGP network design concepts apply to the IPv6 IGP network design
IPv6 IGPs have additional features that could lead to new designs
IPv4 and IPv6 Perspective
• The similarities between the IPv4 and IPv6 IGP lead to
similar network design considerations as far as routing
is concerned.
• The implementation of the IPv6 IGPs achieves parity
with the IPv4 counterparts in most aspects but this is
an ongoing development and optimization process.
• Coexistence of IPv4 and IPv6 IGPs is a very important
design consideration.
Convergence – How does it work ?
Four steps to convergence:
•Detect the failure
•Propagate the Failure
•Calculate new routes around the topology change
•Add changed routing information to the routing table
• All four steps are similar for any routing protocol.
• Note: Step 1 is for tuning your speed of convergence by
how fast you detect network reachable issues.
• But, it’s important to keep the others in mind, since
they often impact convergence more than
the routing protocol does
Steps to convergence:
Downtime Analysis
Total Downtime will be determined the following components;
Detect the failure (Loss of signal, keep alive, and etc.)
Propagate the failure (Routing protocol, CAPWAP, STP, and etc.)
Process the failure (Calculate SPF, Node switch-over, and etc.)
+ Update the Routing/Forwarding Tables, re-establish new sessions = Total Downtime (End-to-End
Convergence)
Convergence Summary
• IS-IS with default timers
• OSPF with default timers
• EIGRP without feasible
successors
• OSPF with tuned timers
• IS-IS with tuned timers
• EIGRP with feasible successors
0
7000
6000
5000
4000
3000
2000
1000
1000
2000
3000
4000
5000
Route
Generator
A
B C
D
Routes
Millis
ec
on
ds
IPv4 IGP Convergence Data
Design and Topology Considerations
Topology Summary
• Rules of Thumb
•EIGRP performs better in large scale hub and spoke
environments
•Link state protocols (OSPF, ISIS) perform better in full
mesh environments, if tuned correctly
•EIGRP tends to perform better in more strongly hierarchical
network models, link state protocols in flatter networks
•Note: With IPv6 a great deal of emphasis is placed on
hierarchical addressing schemes. EIGRP thus becomes
very well suited to support such designs
OSPFv2-v3
RIP2-RIPNG
EIGRP –EIGRP v6
• Clear separation of the
two control planes
• Non-congruent
topologies are very
common if not desired
in deployments
• Requires less resources
• Might provide a more
deterministic co-
existence of IPv4
and IPv6
Single Process/Topo
ISIS
The Coexistence Twist
* Today most IPv6 IGPs are distinct from their IPv4 counterparts and will run as ships in the night. The only exception is ISIS.
Protocol Management
Debugs Event Log Neighbor Logging
SNMP
OSPF Neighbor and
Protocol Events
Yes, but Not Easy to Read
Yes Rfc1253
IS-IS Neighbor and
Protocol Events
No No No
EIGRP Neighbor and
Protocol Events
Yes, Moderately Difficult to
Read
Yes Yes
IPv6 Routing Protocol Configuration Examples from a Network Routers Perspective
22
OSPFv3 IPv6
STUB ROUTER
ipv6 unicast-routing
ipv6 cef
! interface serial 0/0
no ip address
ipv6 enable
ipv6 address 2001:ABAB::/64 eui-64
ipv6 ospf 1 area 2
! ipv6 router ospf 1
router-id 3.3.3.3
area 2 stub
!
ABR1 Router
ipv6 unicast-routing
ipv6 cef
!
interface FastEthernet0/0
no ip address
speed auto
ipv6 address 2003::1/124
ipv6 enable
ipv6 ospf 1 area 0
!
interface Serial0/0
no ip address
ipv6 address 2002:ABAB::/64 eui-64
ipv6 enable
ipv6 ospf 1 area 2
!
ipv6 router ospf 1
router-id 1.1.1.1
area 2 stub no-summary
!
ASBR Router
ipv6 unicast-routing
ipv6 cef
!
interface FastEthernet0/0
no ip address
ipv6 address 2003::2/124
ipv6 enable
ipv6 ospf 1 area 0
!
interface Serial0/0
no ip address
ipv6 address 2003::1:1/124
ipv6 enable
ipv6 rip EXT enable
!
ipv6 router ospf 1
router-id 2.2.2.2
default-metric 25
redistribute rip EXT metric-type 1 include-connected
!
ipv6 router rip EXT
redistribute ospf 1 match internal external 1 external 2
include-connected
!
External Router
ipv6 unicast-routing
ipv6 cef
!
interface Loopback0
no ip address
ipv6 address 2004:ABAB::/64 eui-64
ipv6 enable
ipv6 rip EXT enable
!
interface Serial0/0
no ip address
ipv6 address 2003::1:2/124
ipv6 enable
ipv6 rip EXT enable
!
ipv6 router rip EXT
23
EIGRP IPv6
IPv6 EIGRP and IPV4 EIGRP are very similar in concept except for the following
differences:
IPv6 is configured on interface basis and networks are advertised based on
interface command.
When configured on interface, IPv6 EIGRP is initially placed in “shutdown” state.
As with OSPFv3, IPv6 EIGRP require a router-id in IPv4 format.
Passive interfaces can only be configured in the routing process mode.
Need for extra memory resources and supported in IOS 12.4(6)T and later.
24
RIPNG IPv6
25
ISIS IPv6 interface Loopback0
description LOOP0
ip address 198.108.10.37 255.255.255.255
ipv6 address 2607:F018:0:20::1E/128
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
interface Vlan2279
description abcde
ip address 198.108.11.81 255.255.255.254
ipv6 address 2607:F018:0:FFD4::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
interface Vlan2280
description fghij
ip address 198.108.11.83 255.255.255.254
ipv6 address 2607:F018:0:FFD5::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
router isis 1000
net 49.0001.1981.0801.0037.00
passive-interface default
no passive-interface Vlan2279
no passive-interface Vlan2280
!
address-family ipv6
multi-topology
redistribute static
exit-address-family
!
ip forward-protocol nd
!
end
26
BGP IPv6
interface Loopback0
description O-LOOP
ip address 192.12.80.2 255.255.255.255
no ip redirects
ip flow ingress
ipv6 address 2607:F018:FFFF::2/128
!
interface TenGigabitEthernet1/1
description L3
ip address 192.12.80.13 255.255.255.254
ip flow ingress
ip pim sparse-mode
ipv6 address 2607:F018:FFFF:D::2/126
!
router bgp 36375
neighbor 2607:F018:FFFF::1 remote-as 36375
neighbor 2607:F018:FFFF::3 remote-as 36375
!
address-family ipv6
neighbor 2607:F018:FFFF::1 activate
neighbor 2607:F018:FFFF::3 activate
network 2607:F018::/32
exit-address-family
!
end
OSPF v2 interface Vlan2378
description To-Cool –for-school
ip address 198.108.11.185 255.255.255.0
ip pim sparse-mode
ipv6 address 2607:F018:0:FF91::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
interface Vlan2379
description To-Cool1
ip address 198.108.12.187 255.255.255.0
ip pim sparse-mode
ipv6 address 2607:F018:0:FFAD::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
router ospf 211
log-adjacency-changes detail
area 0.0.0.3 nssa no-summary
passive-interface default
no passive-interface Vlan2378
no passive-interface Vlan2379
network 198.108.0.0 255.255.0.0 area 0.0.0.3 !
27
ISIS v6 interface Vlan2378
description To-Cool –for-school
ip address 198.108.11.185 255.255.255.0
ip pim sparse-mode
ipv6 address 2607:F018:0:FF91::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
interface Vlan2379
description To-Cool1
ip address 198.108.12.187 255.255.255.0
ip pim sparse-mode
ipv6 address 2607:F018:0:FFAD::3/127
ipv6 enable
ipv6 router isis 1000
isis network point-to-point
!
router isis 1000
net 49.0001.1981.0801.0043.00
log-adjacency-changes
passive-interface default
no passive-interface Vlan2378
no passive-interface Vlan2379
!
address-family ipv6
multi-topology
redistribute static
exit-address-family
!
ip forward-protocol nd
Dual Stack
Summary
Is one protocol better than the others?
Which routing protocol should I use in my network?
Should I switch from the one I’m using?
Do the same selection rules apply to IPv4 and IPv6?
How will my IPv4 and IPv6 routing protocols coexist?
Did we answer this question???
29
Summary
• There is no “right” answer!
• Consider:
•Your business requirements
•Your network design
•The coexistence between IPv4 and IPv6
•Intangibles
• The three advanced IGP’s are generally pretty close in
capabilities, development, and other factors
Expertise (Intangible)
• What is your team comfortable with?
• What “escalation resources” and other support avenues
are available?
• But remember, this isn’t a popularity contest—you don’t
buy your car based on the number of a given model sold,
do you?
• An alternate way to look at it: what protocol would you like
to learn?
Q and A